1. Field of the Invention
The invention relates to chain stitch sewing machines.
2. Description of the Prior art
Single thread chain stitch sewing machines with pivoted thread seizing loopers are commonly used for sewing buttons onto garments and for hemming or tacking. Such a machine may be seen, for example, in U.S. Pat. No. 4,411,210 of Karl H. Killinger for "Actuating Mechanism for a Double Pointed Looper in a Sewing Machine" which issued Oct. 25, 1983.
A machine as described in said patent includes a pivotably mounted cam having a looper affixed thereto, and spring means which biases the looper cam assembly axially to a position wherein tracks in the cam are disposed for engagement with a cam actuator, and a gate for controlling access to the cam tracks is disposed for interaction with a gate regulating spring. During operation of the machine, the looper is pivoted to bring looper points into cooperation with a sewing needle and so provide for the formation of chain stitches. However, faulty operation is sometimes experienced due to engagement of the gate regulating spring with the rear face of the gate when loop penetration should occur, and a consequent movement of the looper cam assembly in oppostion to its axial bias sufficient to result in skipped stitches.
It is a prime object of the present invention to provide an improved chain stitch sewing machine in which a gate regulating spring is prevented from axially deflecting a looper cam assembly.
It is another object of the invention to provide an improved chain stitch sewing machine in which a gate regulating spring is lifted to the top of the gate for passage from one side of the gate to the other during pivotal reciprocation of a looper cam assembly.
Other objects and advantages of the invention will become apparent during a reading of the specification taken in connection with the accompanying drawings.